HOUSTON -- Like staff mate Dallas Keuchel but to an even greater extent, Houston right-hander Charlie Morton has been more observer than participant in recent weeks because of the Astros' success combined with off days that are part of the annual postseason schedule.

When Morton starts Game 4 of the American League Championship Series against the Boston Red Sox on Wednesday at Minute Maid Park with the Astros trailing 2-1 in the series, it will be his first appearance since Sept. 30.

Morton toed the rubber in the regular-season finale against the Baltimore Orioles and worked just three innings by design, capping an odd final month that saw him limited to 15 innings in four starts because of lingering right shoulder discomfort.

Given the confluence of his extended break and those health concerns, the expectations for how deep into the game Morton might work against the Red Sox are unknown.

"I know he feels the best he's felt in the last month or so, which is a good sign," Astros manager A.J. Hinch said of Morton. "That's what he said (Monday). I think adrenaline will go a long way. So I think you have to watch pitch quality. I have to be prepared for him to go three innings like he did in Baltimore or if he's cruising (more than that).

"We know our players so we'll know when fatigue is starting to set in or when he's not feeling it or if he starts spraying the ball a little bit. I'll be pretty aggressive with the bullpen (Wednesday) if need be, but I don't want to doubt Charlie from the get-go and all of a sudden be looking for a problem that doesn't exist."

Morton isn't entering his sixth career postseason start with any pre-set limitations.

"I'm assuming that they'll let me go as far as I'm effective," said Morton, who was 2-1 with a 4.24 ERA in the 2017 postseason. "As far as the pitch count, I don't know why there would be a pitch count."

Right-hander Rick Porcello (1-0, 1.35 ERA this postseason) will start for the Red Sox. Porcello has toggled between the rotation and the bullpen this postseason, working in relief in Game 1 of the AL Division Series against the New York Yankees before pitching five solid innings and locking up the decision as Boston clinched that series in Game 4 at Yankee Stadium on Oct. 9.

Porcello is following the same path against the Astros. He completed a scoreless eighth inning and had two strikeouts in Game 2 at Fenway Park, handing the ball to closer Craig Kimbrel in that 7-5 victory. The immediacy of relief work has yielded a more emotional response from Porcello, who deems it prudent to wrangle his emotions when he pitches starting in the first.

"I don't know that I'm pitching with more emotion," Porcello said. "I think as a starter you're trying to cover the course of a whole ballgame," he said. "So you're kind of trying to keep your emotions in check just because you've got a lot of baseball to pitch. You don't want to get too high, too low, whatever it is.

"But I feel like I've had the last inning of the start if I get a big out, big strikeout, I've shown emotion the same as I have coming out of the bullpen. So really I don't feel like I'm doing anything different besides trying to lock down those three outs and it's just about that one inning for me. I don't have to worry about facing a lineup three times through and covering a whole ballgame."